SAGD or Steam Assisted Gravity Drainage is a method for extracting liquid hydrocarbons from tar sand type deposits. Due to the bituminous condition of the hydrocarbon reserves in such deposits, flow by conventional means does not occur at all or at a rate that can support any commercial activity. Utilizing steam to heat the formation so that the hydrocarbon deposits can flow allows production of the deposits. Generally, SAGD systems utilize two or more boreholes where one or more is a producer well and one or more is an injector well. The injector wells are utilized to inject high temperature steam into the formation to heat the same and thereby reduce the viscosity of the bituminous deposit sufficiently to allow flow thereof. The production wells catch the flowing hydrocarbon and ferry it to surface for further processing.
Existing systems designed to perform the method discussed above are functional but require cooling of the wellbore if components need to be removed to surface for servicing. This is because the components are so hot from steam injection that they are difficult to handle at the rotary table. Further, many of the components are badly distorted by recovery to surface due to the high temperature at which they are pulled from the wellbore.
In view of greater demand for oil and other hydrocarbon products, more efficient means of extracting hydrocarbons from tar sand type deposits will be well received by the art.